Apparatus and process for drying wood



APPLICATION FILED SEPT. 213| 1920.

Patentd Apr. 18, 1922.

; TES

KAK''JI VEUJINO, OF LOS ANGELES, CALIFORNIA.

APPARATUS AND :PROCESS FOR DRYING WOOD.

IAISMS.

Specification of Letters Patent. v Patgnted Alpin 18, 1922.

Application filed September 28, 1920. Serial No. 413,392.

To all whom t may concern: l

Be it known that I, KAKUJI FUJINO, a subject of the Emperor of Japan, residing in the city and county of Los Angeles, and State of California, have invented a knew and useful Apparatus and Process for Drying lVood, of which the following is a specification.

This invention relates to an improved apparatus and process for drying wood. An object of the invention is to provide a process whereby a better quality of lumber is produced, and whereby all the preservative elements in the wood are retained.

Another object is to provide a process whereby the volatile elements in the wood are extracted and replaced by preservative elements derived from the carbonization of green wood. e

Another object is to provide a process 1n which the wood is subjected to smoke, gases and vapors derived from the carbonization of lofreen wood or brush of like character.

nother Objectis to provide anv apparatus inwhich the smoke utilized in the process is derived from a charcoal manufacturing furnace. e

Another obj ect is to provide an apparatus comprising a combustion chamberfor the carbonization of green wood and means conveying the products of such carbonization to a wood drying chamber containing the wood to be dried.

Another object is to evolve a process whereby a by-product of charcoal is produced.

Various other objects and advantages will be more fully apparent from the following description of the accompanying drawings which form a part of this disclosure, and which illustrate a preferred form of embodiment of the invention.

Of the drawings:

Figure l is an end view of a wood drying apparatus embodying the present invention;

Figure 2 is a perspective view of the apparatus;

Figure 3 is a longitudinal section through the apparatus. Perfect desiccatlon of wood without injury to its Ystructure should consist of perfect preservation of its fibrous and other insoluble components intact, coupled with a perfect removal of its soluble components.

In utilizing for this purpose the products of the carbonization of green wood in a charcoal manufacturing furnace I employ a smoke containing such volatile elements as acetic acid, methyl alcohol, acetone, creosote, tar, etc., which are distilled from the green wood by heat and which has a better dissolving effect on like elements contained in the green wood to be dried. Smoke produced from any other Vmaterial than green wood would not contain such elements as would have an eiiicient dissolving action on the like elements in the lumber and would not, therefore, give the superior results sought.

Among the constituents of wood we find fibrous matter and wood juices, besides lignos, sugars', starches, gums, tannin, chromatin material and proteids, all of which vary in quality and quantity according to the kinds of woods, climate, soil and time of cutting.

Taking these facts into consideration I discoveredthat smoke derived from the carbonization of a certain kind of green wood or brush had a vastly more eflicient effect upon lumber of the same kind, that is, smoke derived from green oak gave'a much better result in the curing of oak lumber than smoke derived from any other source, likewise smoke lderived from green maple gave the best result in the curing of maple lumber. Therefore, in the present invention it is preferable to cure the lumber by the application thereto of the products of the carbonization of green wood having approximately the same chemical components as the wood to be cured.

By the usefof this apparatus and process I have provided a means for economically drying lumber in a manner which produces a high quality product which will not develop cracks on exposure to the weather, which will retain its natural color, odor, and preservative elements, and which has absorbed additional amounts of such elements.

In general terms my improved apparatus subjects the lumber to be dried, to smoke produced by the slow carbonization of green wood, the smoke gradually varying in its vapor contents and temperature from a low temperature saturated smoke to a high temperature dry smoke,'and also varying in its chemical components as they are progressively distilled from the green wood by the increasing heat of combustion.

In the process the smoke first acts to expand the brous structure of the lumber and to dissolve certain soluble elements contained therein and subsequently as the smoke increases in temperature and decreases in vapor contents the soluble and volatile ele,- ments in the lumber are abstracted. Circulation in the lumber drying chamber is then prevented vvith said chamber filled with dry smoke of high temperature and is ma1ntained closed until the temperature therein reduces to normal, with the result that the lumber becomes impregnated by preservative elements carried by the high temperature smoke in the form of gases, such gases being` reduced to their natural state during` the cooling to normal temperature.

In the drawings7 11 designates a charcoal furnace providing a combustion chamber '32, and 18 designates a kiln providing a drying chamber 30. The Wall 13 of the furnace 11 is provided with a door 12 through Which the combustion chamber 32 is charged with the charcoal producing material 15,'and near the base 17 the door has a damper 14- through Which air may be admitted to control the fire. A pipe 16 communicates With the chamber adjacent the base 17 and extends upwardly, said pipe having an open end 20 provided with a damper 19. A cross pipe 22 is also provided With a damper 21 and connects with the pipe 16 to direct the products of combustion into the upper portion of the drying chamber 30. An exhaust pipe 24rcommunicating With the chamber 30 adjacent the base 23 extends upwardly and has an open upper end 26 provided with a damper 25. 27 designates a pile of lumber in the form of logs, Which has been placed in the drying chamber for drying. Doors 28 aiford access to the drying chamber for removing the dried lumber and for charging the chamber with material to be dried and a thermometer 29 is provided for indicating the approximate temperature of the drying chamber. The furnace 11 is provided With VWindows 31, through Whih the operator may from time to time examine the contents of the combustion chamber 32.

By this arrangement I have provided a combustion chamber or charcoal furnace in which green Wood is carbonized by a slow combustion ina substantially dead air space, only enough air being admitted to eiiiciently promote the carbonization of the green Wood and drive off the soluble and volatile elements thereof.- In the operation of my rape paratus the pile of green Wood in the combustion is fired at the top, this assuring a very slow combustion by reason of the downward progression of the lire being in opposi- Y tion to the natural upward progressive tendency of fire and heated elements.

In use, the V drying chamber is charged with the material to be dried and the comdischarging into the drying chamber acts Y to expand the pores of the lumber and dissolve the soluble and volatile elements therein and convey them out through the exhaust pipe 24. As the heat produced in the com-j bustion chamber increases the character of Athe smoke changes for the reason that as the iire becomes hotter different chemical elements contained in the green Wood are given ofi. It has been found that each `of such chemical elements has its most etlicient dis# solving action on like chemical elements in the lumber to be dried and as the lumber to be dried is normally in a green state, it VWill for vthis reason be evident that the chemical elements distilled from the green Wood in the combustion chamber will mostel'ectively dissolve and carry off the soluble and volatile chemical elements co-ntained in the lumber inV the drying chamber.

At higher temperatures `the combustion gives off various preservative elements such as Wood-tar and ereosote and as the material in the combustion chamber reachesthe condition of a burningmass producing no more smoke the dampers 21 and 25 Vofthe drying chamber are closed to retainsaid chamber filled With the smoke and gases of relatively high temperature. The chamber 30 is mainy tained in such smoke filled air tight condition until its temperature is reduced to normal and the lumber has become impregnated With the preservative elements.

After the dampers 21 and 25 are closed, the dampers 14' and 19'of thecombustion chamber are regulated to properly complete the charcoal producing operation. .Y

Having described my invention, I claim: 1. The process of drying Wood, consisting of subjecting the Woodto be dried to theV action of the soluble and volatile products derived from the carbonization of green Wood.

2. The process of drying Wood, consisting ofsubjecting the Wood to be dried to the action ofthe soluble and volatile products derived from the carbonization of green `VWood of like character.

3. The process of dryingwood, consisting y of carbonizing green Wood bythe application of a gradually increasing heatto prof ducesmoke progressively varying in vapor contents, temperature and chemical components, subjecting Wood to be dried to such smoke, and subsequently maintaining the smoke of highest temperature in contact With the Wood to be dried until its temperature reduces to normal.

4. In a Wood drying apparatus, a combus tion chamber having draft means only adjacent its base, means for supplying a limited amount of air to said chamber, a drying chamber having an exhaust opening adjacent its base, a pipe conveying products of combustion from the lower portion of the combustion chamber to the upper portion of the drying chamber, means for closing said exhaust opening, a damper for closing said pipe, and means between said damper and the combustion chamber for effecting a dis charge of the products of combustion to the atmosphere When the damper is closed.

5. In a Wood drying apparatus, a combustion chamber, means or supplying a limited amount of air to said chamber, a drying chamber having draft means only adjacent its base, a pipe conveying the products of combustion from the bottom portion of the combustion chamber to the top portion of the drying chamber, an exhaust pipe extending from the bottom portion of the drying chamber, and dampers for controlling the draft through both chambers and for controlling communication between the chambers.

In testimony whereof, I hereunto aix my signature, this 7th day of September, 1920.

KAKUJ I FUJINO 

